How do I bake/add material colors onto my UVmap?
Befor baking you need to open the Node editor and there add an image to bake to.

It is very important that this Image Texture node is selected before baking.

1: Open a node editor window.

2: Put a check against the Use Nodes option.

3: Add an Image Texture node.

4: Load the image that you want to bake to into the Image Texture node.

5: Before leaving the Node editor make sure that the Image Texture node is selected.

6: Hit that bake button.



Hope this helps some  :)